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Shigeki Unjoh - One of the best experts on this subject based on the ideXlab platform.

  • SEISMIC DESIGN OF Highway Bridges
    Journal of JAEE, 2004
    Co-Authors: Kazuhiko Kawashima, Shigeki Unjoh
    Abstract:

    The Hyogo-ken-Nanbu (Kobe) Earthquake of January 17, 1995, caused destructive damage to the Highway Bridges. Based on the lessons learned from the Kobe Earthquake, the seismic design specifications for Highway Bridges were significantly revised in 1996. The intensive earthquake motion with a short distance from the inland-type earthquakes with Magnitude 7 class as the Kobe Earthquake has been considered in the seismic design. This paper summarizes the seismic design specifications for Highway Bridges after the 1995 Kobe Earthquake.

  • Seismic Isolation Design Code for Highway Bridges
    Seismic Engineering Volume 2, 2002
    Co-Authors: Kazuhiko Kawashima, Shigeki Unjoh
    Abstract:

    This paper presents the seismic isolation design code for Highway Bridges. This is based on the 1996 Design Specifications for Highway Bridges, Part. V: Seismic Design, issued by the Japan Road Association in December 1996. This paper focuses on the outlines of the seismic isolation design code including the seismic design basic principles, design ground motion, and seismic isolation design.Copyright © 2002 by ASME

  • Seismic retrofit of existing Highway Bridges in Japan
    Cement and Concrete Composites, 2000
    Co-Authors: Shigeki Unjoh, Toru Terayama, Yukio Adachi, Jun-ichi Hoshikuma
    Abstract:

    Abstract This paper presents the current technical developments for seismic design and seismic retrofit of existing Highway Bridges in Japan. At first, the histories of the past seismic design codes, past seismic evaluation investigation, and past seismic retrofit practices for Highway Bridges are described. Then the damage caused by the 1995 Hyogo-ken Nanbu Earthquake and the lessons learned from the earthquake are briefly described. Finally, the seismic retrofit program after the Hyogo-ken Nanbu Earthquake is described with emphasis on research and development as well as field practice of the seismic retrofit of existing reinforced concrete Highway Bridges such as single column bent, wall-type pier, and multicolumn bents.

  • the damage of Highway Bridges in the 1995 hyogo ken nanbu earthquake and its impact on japanese seismic design
    Journal of Earthquake Engineering, 1997
    Co-Authors: Kazuhiko Kawashima, Shigeki Unjoh
    Abstract:

    The Hyogo-ken Nanbu Earthquake of 17 January 1995, caused destructive damage to Highway Bridges. Obviously, this was the first experience of such destructive damage since the Great Kanto Earthquake of 1923. Various tentative measures were taken for seismic design of repair and reconstruction of Highway Bridges which were damaged due to the earthquake. This paper summarises the damage feature of Highway Bridges and a series of actions taken for seismic design and seismic strengthening of Highway Bridges about half a year following the earthquake.

  • impact of hanshin awaji earthquake on seismic design and seismic strengthening of Highway Bridges
    Doboku Gakkai Ronbunshu, 1997
    Co-Authors: Kazuhiko Kawashima, Shigeki Unjoh
    Abstract:

    The Hanshin/Awaji Earthquake (Hyogo-ken Nanbu Earthquake) of January 17, 1995 caused destructive damage to Highway Bridges. Obviously this was the first experience to suffer such destructive damage since the 1923 Great Kanto Earthquake. Various tentative measures were taken for seismic design of repair and reconstruction of Highway Bridges which suffered damage due to the earthquake. This paper summarizes the damage feature of high way Bridges and a series of actions taken for seismic design and seismic strengthening of Highway Bridges in about half year since the earthquake.

Kazuhiko Kawashima - One of the best experts on this subject based on the ideXlab platform.

Dan M Frangopol - One of the best experts on this subject based on the ideXlab platform.

  • sustainability informed maintenance optimization of Highway Bridges considering multi attribute utility and risk attitude
    Engineering Structures, 2015
    Co-Authors: Samantha Sabatino, Dan M Frangopol, You Dong
    Abstract:

    Abstract Throughout their service life, Highway Bridges deteriorate due to increasing traffic loads and aggressive environmental conditions. Aging of materials can have significant effects on the structural performance of Highway Bridges. A comprehensive risk assessment procedure is crucial in evaluating and ultimately mitigating detrimental consequences of structural failure to the economy, society, and the environment. The proposed sustainability-based maintenance optimization decision-support framework provides decision makers with optimal life-cycle maintenance actions that balance conflicting objectives. Utility theory is employed herein in order to effectively capture the sustainability performance of Highway Bridges and impact of the decision maker’s risk attitude. The main objective of this framework is to reduce the extent of the consequences of structural failure to the economy, society, and the surrounding environment. The capabilities of the proposed approach are demonstrated on an existing Highway bridge.

  • risk assessment of Highway Bridges under multiple hazards
    Journal of Risk Research, 2011
    Co-Authors: Alberto Deco, Dan M Frangopol
    Abstract:

    The aim of this paper is to provide a rational framework for the quantitative risk assessment of Highway Bridges under multiple hazards. Risk is a crucial indicator to be considered when managing structures of great importance such as Highway Bridges. It associates the consequences of a structural failure or malfunction with the probability of bridge failure. Time-dependent total risk is computed and the effect of structural redundancy is investigated and implemented. The proposed framework includes the estimation of the effects of multiple common hazards such as abnormal traffic loads, environmental attacks, scour, and earthquakes. The failure probabilities associated with the considered hazards are evaluated separately using different approaches. Time-dependent failure probabilities, hazard functions, and probability density functions of the time-to-failure are also assessed for each hazard. These assessments contribute to the evaluation of risk considering the traffic flow and the local economy at the bridge location. Both epistemic and aleatory uncertainties are considered in this approach. Time-dependent profiles of risk, accounting for direct and indirect consequences, are obtained for an existing Highway bridge.

  • reliability based life cycle management of Highway Bridges
    Journal of Computing in Civil Engineering, 2001
    Co-Authors: Dan M Frangopol, Jun Sik G Kong, Emhaidy S Gharaibeh
    Abstract:

    The objective of bridge management is to allocate and use the limited resources to balance lifetime reliability and life-cycle cost in an optimal manner. As the 20th century has drawn to a close, it is appropriate to reflect on the birth and growth of bridge management systems, to examine where they are today, and to predict their future. In this paper, it is attempted to shed some light on the past, present, and future of life-cycle management of Highway Bridges. It is shown that current bridge management systems have limitations and that these limitations can be overcome by using a reliability-based approach. It is concluded that additional research is required to develop better life-cycle models and tools to quantify the risks, costs, and benefits associated with Highway Bridges as well as their interrelationships in Highway networks.

  • repair optimization of Highway Bridges using system reliability approach
    Journal of Structural Engineering-asce, 1999
    Co-Authors: Allen C Estes, Dan M Frangopol
    Abstract:

    As reliability based methods gain increased acceptance, there is greater opportunity to use scarce resources more efficiently while maintaining a prescribed level of reliability of a structure throughout its service life. The goal is to provide management decisions that will balance lifetime system reliability and expected life-cycle cost in an optimal manner. This study proposes a system reliability approach for optimizing the lifetime repair strategy for Highway Bridges. The approach is demonstrated using an existing Colorado State Highway bridge. The bridge is modeled as a series-parallel combination of failure modes, and the reliability of the overall bridge system is computed using time-dependent deterioration models and live load models. Based on an established repair criterion, available repair options, repair costs, and updating, the optimum lifetime repair strategy is developed. The sensitivity of the optimum strategy to changes in various problem parameters including the prescribed service life,...

  • REDUNDANCY IN Highway Bridges
    Engineering Journal, 1991
    Co-Authors: Dan M Frangopol, Rachid Nakib
    Abstract:

    This study reviews definitions of deterministic and probabilistic system redundancy measures which could be used in the design and evaluation of Highway Bridges. Some of these measures are used to evaluate the redundancy of an existing steel girder bridge. In this context, corrosion and accidental damages are simulated and the bridge redundancy is evaluated by using three-dimensional nonlinear finite element and probabilistic system analyses. The bridge damage-redundancy-reliability interaction is also studied.

D J Cole - One of the best experts on this subject based on the ideXlab platform.

  • effects of vehicle suspension design on dynamics of Highway Bridges
    Journal of Structural Engineering-asce, 1995
    Co-Authors: Mark F Gree, D Cebo, D J Cole
    Abstract:

    The dynamic response of short-span Highway Bridges in relation to heavy vehicles with leaf-spring and air-spring suspensions is examined in this paper. Calculation of the dynamic bridge responses is accomplished by separately modeling the bridge and vehicle and then combining the models with an iterative procedure. The bridge model is obtained by combining mode shapes with dynamic wheel loads in a convolution integral. Experiments on two Highway Bridges validate the bridge calculation procedure. A leaf-sprung, four-axle articulated vehicle and a vehicle fitted with air suspensions and hydraulic dampers comprise the validated nonlinear vehicle models. The two vehicle models and three different bridge models are combined to predict the dynamic bridge responses. Two surface profiles are used on each bridge: a step up at the entrance, and a pseudo-random profile. Dynamic response increments are used to compare the effects of the two vehicles on Bridges. Results indicate that the air-suspended vehicle causes significantly lower dynamic bridge responses than the leaf-spring suspended vehicle.

Jian Zhang - One of the best experts on this subject based on the ideXlab platform.